package main


func numJewelsInStones(jewels string, stones string) int {
	mj := make(map[byte]struct{})
	for i:=0;i<len(jewels);i++{
		mj[jewels[i]] = struct{}{}
	}
	var res int
	for i:=0;i<len(stones);i++{
		if _,has:=mj[stones[i]];has{
			res++
		}
	}
	return res
}